1. Field of Invention
This invention relates to a tractor mountable box scraper capable of measured and level release of material from the scraper by use of a controlled back plate (moldboard) which is hinged at its junction with one of the side plates and controllably separates from the opposite end side plate.
2. Relevant Prior Art
For years, simple box scrapers have been used to scrape up and drag materials such as soil, road building and like materials from one location to another. The most common uses being to level or create specific grades of soil level, fill in unwanted holes, or simply to remove excess materials.
A box scraper can be described as three sides of a box with neither top nor bottom nor a complete top to bottom front side wall. The back plate (moldboard) of the box is welded to a left side-plate and to a right side-plate, both of which extend forward from their respective side edges of the moldboard. The moldboard can be formed from a single sheet of metal, or comprise two or more plates welded together to form a wall which when viewed from the side has its lower edge situated slightly forward of the upper part of the wall; this being accomplished by a forward tilt of the base of the entire moldboard, or curvature of a portion or all of the back wall, or the angulation forward at the base of the lowest unit of a sectionally formed moldboard.
For greater cutting efficiency, the inferior portion of the moldboard can be formed of a removable section made from a more durable material suitable for use as, and sharpened to act as a cutting blade. The three sided box provides a containment vessel within which the scraped up material can pile up and does pile up as the back side is pulled forward and cuts into the underlying surface material.
The scraped up material is kept from moving side ways and around the ends of the blade by the side plates, necessitating that the whole box assembly be raised vertically in order to drop, or to spread the contained material over a new area at the width of the back blade. Alternatively, the box scraper can be tilted to raise or lower the left side relative to the right side and vice versa. In this tilted manner, piled material can escape but control is difficult, release is not in a level manner and it is easy to gouge the surface of the ground in an undesirable manner with whichever side of the scraper is lower. Elevation of the blade is accomplished by activating a hydraulic ram that is attached to the towing tractor; tilting, is accomplished by controls that are part of the three point hitch assembly of the tractor itself.
A problem arises when it is desired to drop or spread the piled up material to the side of the scraper box because it necessitates multiple and often complex maneuvering of the tractor to do this. Also, to date, box scrapers have not been suitable for berming scraped up material either on the right or on the left on an optional basis. These problems have limited the use of an otherwise versatile tool.